This invention relates to scaffolding systems, and more particularly to a scaffolding arrangement supported on pump jack poles on which are arranged pump jacks for riding up and down the poles.
In various industrial applications, scaffolding is erected in order to give workers access to elevations above a ground surface. By way of example, in the installation of aluminum siding along the exterior of housing, scaffolding is required to permit workers to move up and down adjacent the side of the housing in order to install housing siding. In such cases, the scaffolding is typically erected through the use of pump jack poles which are spaced apart along the side of the house and secured to the house by means of braces. Pump jacks are then utilized to ride up and down the poles. The pump jacks typically include support arms on which are placed scaffolding staging. The workers can stand on the scaffolding staging and operate the pump jacks to move the staging up and down along the pump jack poles.
The aforementioned U.S. Pat. No. 4,382,488 describes a novel pump jack pole formed of elongated hollow metal with a rubberized surface formed on only one side of the metal pole. Such poles were found to be extremely strong, long-lasting, and easier to manipulate than the previously standard wooden poles. An improved brace was described in U.S. Pat. No. 4,446,845 for connecting the pump jack pole to a support surface such as the wall or roof of a housing. A clamp, such as is described in the U.S. Pat. No. 4,432,435 can be used to interconnect the brace to the pole. A pump jack is described in U.S. Pat. No. 4,463,828 and includes improved features for safety purposes and for increased strength. An arrangement is described in U.S. Pat. No. 4,499,967 for interconnecting two elongated staging sections to permit co-linear and co-planar connection of the sections.
The pump jack described in the aforementioned patent, includes a lower arm on which the scaffolding is supported with the scaffolding facing in one direction with respect to the poles. Typically, the scaffolding platform will be oriented in a direction facing from the poles toward the housing. The aforedescribed pump jacks also include an upper arm on which can be placed another platform which can be used as a work bench. In fact, the standard scaffold staging which is used as a platform on the lower arms, can actually be inverted when placed on the upper arms and will provide for a deep trough which can be used as a work bench for storing supplies. The spacing between the lower arms and the upper arms is such that an individual standing on the staging platform on the lower arms can easily reach into the work bench on the upper arm.
In utilizing such arrangement, the space between the upper and lower layers of scaffolding staging is generally open and can result in accidental falling of the worker between the layers. Additionally, the possibility of having tools fall also exist. Tools falling off provides both an inconvenience, and it can also be a danger to anyone standing beneath the staging on the floor below. One solution to such a safety problem is presented in the aforemention U.S. Pat. No. 4,598,794. In such patent, there is described a side rail system for interconnecting layered sections of elongated scaffold staging. The side rail system includes upright posts, which are spaced along the staging. A pair of rods are respectively associated with the top and bottom of each post. The rods are pivotally connected to the posts and are inserted into the upper and lower layers of the staging and secured by means of quick connect arrangements. A mid rail as well as a toe board can then be horizontally connected to the rails. An end rail system is also described.
While such side rail system has been found to be extremely effective and providing a safety improvement, other safety arrangements would appear useful as well.